Typewriting machine



W. A. DOBSON.

TYPEWRITING MACHINE.

APPLICATION FILED Mn. 30. 1920.

Patented May 30, 1922.

I NVE-N Ton:

WILLIAhI A. DOBSON, OF HARTFORD, CONNECTICUT, ASSIG-NOR TO UN DERWOOD TYPE- WRITER COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

TYPEWRITING MACHINE.

Specification of Letters Patent.

Application filed. April 30, 1920. Serial No. 377,750.

To all whom it may concern Be it known-that I, WILLIAM A. DOBSON, a citizen of the United States, residing in Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Typewriting Machines, of which the following is a specification.

This invention relates to typewriting machines, such as the'Underwood portable typewriting machine disclosed in my Patent No. 1,335,956, dated-April 6, 1920. In such and other machines, the case-shift mechanism is preferably adapted to be locked in the shifted position to enable upper-case types to print, as is also true in the larger machines. In these small machines, however, since the mechanism is necessarily built of small parts, certain difiiculties arise in making the case-shift lock work satisfactorily. In the larger machines, a case-shift lock can usually be adapted to hold the case-shift mechanism at the limit'o-f its throw, even if the lock has a little lost motion, because the length of the key-lever allows the key-lever to spring sufficiently to take up the required lost motion, without involving any move ment of the case-shift mechanism proper.

Looks, like those used in the larger maretained, the parts must be kept as light as possible and yet have the requisite stiffness. To obtain uniform alignment at the case shift operation, it has been found sufficient to provide a lock-armfor the case-shift key,

which, when swung to effective position, engages the case-shift keyle'ver by friction and holds it substantially without move- -ment, while pressure'upon the cast-shift key is suificient to allow the lock to be released. It has been found possible to obtain this result by providing a lock-arm which swings over a lug on the case-shift key, in

such a manner that the arm, instead of engaging over the lug, so that a substantial depression of the caseshift key would be necessary to release the arm, engages therewithwith suflicient friction to be retained against the tension of the spring, which normally tends to make the arm ineffective. Pressure upon the key will cause the keylever to yield slightly, but sufficiently to enable its lug to release the arm.

To make such a mechanism a practical comercial article, it has been found that the lug must be slightly adjustable upon the key-lever to allow for slight inequalities in the stamping or in the final shaping of the parts, since the adjustments are necessarily very fine.

According to the present invention, the lug, instead of being fast upon the key-lever, may be movable thereon, and, in the form herein illustrated, is shown as part of a member pivoted upon the key-lever and provided with an adjusting screw adapted to be variably set to co-operate with the lock arm. Since the machine in the patent above referred to has two shift-key-levers shifting to diiferent cases, each lever may have its lug upon such a pivoted member, and adjustable in the manner described.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a perspective view of a pair of shiftkey-levers of the kind described,

showing the present invention as applied thereto.

Figure 2 1s a slde view of the same, showmg parts 1n normal position.

Patented May 30,1922.

Figure 3 is a view similar to Figure 2, but

showing the figure shift-key depressed and locked. I

In the Underwood standard portable typewriting machine, the character-keys 1 may be used to print either in lower case, capital case, or figure case, by means of types not shown herein. Normally they print in lower case. When it is desired to print in the figwhich is adapted to lift the shift-frame 7 of the typewriting machine from its normal Figure 2 position to the Figure 3 position.

Indoing this, the figure shift-key 2 causes a lug 8 near the rear end of its key-lever to lift a rock arm 9, and rock to ineffective position a capital-shift stop 10, which normally isadapted to arrest the shift-frame 7 when the capital-shift-key is depressed. The rocking carries the stop 10 clear of the shiftframe and allows the shift-frame to rise until a lip 11 thereon strikes the figure-caseshiftstop 12.

When in the Figure 3 position, the shift key 2 is adapted to be locked by depression of a finger-piece 13, formed as a rock-arm having a lower extension or arm 14, which, at the depression of the finger-piece, swings forwardly over a lug 15 on the key-lever 3. When the key-lever 3 is in its Figure 3 po sition, the lower end 16 of the arm 14 frictionally engages the point 17 of the lug 15, and is held there by friction against the tensionof the spring 18, which normally tends .to return the arm 14 and finger-piece 13.

To enable the accurate adjustment of the lug 15 to hold the arm 14, the lug is formed as a rear end of a member 19, pivoted at 20 upon the key-lever 3, and the lug is adapted tobe shifted or raised by turning a screw 21 threaded into a lip 22 on the member 19, overlying thekey-lever 3. It has been found suflicient to rely upon gravity or friction to hold the member 19 down upon the keylever. The arm 14 is behind a front plate 23 of the typewriting machine, and the member 19 extends from in front of the plate to the back thereof, thus rendering it easy to adjust the screw 21 without disassembling the machine at all.

The capital-shift-key 24 is adapted to be locked in the same way by a locking arm 25 which may be formed out of the same fiat piece of metal as the arm 14, and may be connected thereto by a bent-over rocking bail 26. The canital-shift-key 24 is provided with a lug 27 which may be like the lug 15, being the rear end of a member 28, pivoted at 29 uponthe key-lever 30 of the shiftkey 24, which, likethe key-lever 3, is pivoted at 4. The arms 14 and 25 may be j ournaled upon a shaft 31, mounted in brackets 32 on the rear side of the plate 23. Since the bottom 16 of the arm 14 and the bottom 33 of the arm 25 are about concentric with the shaft 31, depressing either the key 2 or the scope of the invention, and portions of the improvements may be used without others. Having thus described my invention, I claim: I

1. In a type'writing machine having a front wall, in combination,- a case-shift mechanism, a case-shift key-lever projecting through said front wall, a movable locking .membe'r back of the front wall, a lug back of said wall and shiftably supported on said key-lever, and means actuable at the front of said wall for variably adjusting the lug on the lever.

member back of the front wall, a lug back of said wall and shiftably supported on said key-lever, means actuable at the front of said Well for variably adjusting the lug on the lever, means normally urging said looking member to ineffective position, and means actuable at the front of said wall for shifting said locking member to effective position.

3. In a typewriting machine, the combination with a case-shift mechanism, of a caseshift key-lever, a locking arm for said lever, a stop for arresting the throw of'the lever, a member pivoted to swing on the lever, a lip on said member-overhanging the lover, a screw threaded intothe lip to bear against the lever to limit the throw of the member, and a lug on the member adapted to be engaged'by the arm to lock the lever.

4. In a typewriting machine, the combination with a case-shift mechanism, of a pair of case-shift key-levers, a locking'arm for each lever, a single finger-piece for shifting said arms into their effective positions, a stop for arresting the throw of each lever, a lug on each lever adapted to becaught'by its arm, and means for independently and variably positioning the lugson their levers.

5. In'a typewriting machine, the combination with a case-shift'mechanism, of a pair of case-shift key-levers, a locking arm for each lever, a single finger-piece for shifting said arms, a stop for arresting the throw of each lever, a member on each lever and pivoted to swing thereon, means for limittion with a case-shift mechanism, of a pair of case-shift key-levers, alocking arm for each lever, a single finger pi'ece for shifting said arms, a stop for arresting the throw of each lever, a member on each lever and pivoted to swing thereon, a lip on each member overhanging its lever, a screw threaded into each lever to limit the throw of its member, and a lug on each member adapted to be engaged by the arm to look its lever.

7. In a typewriti'ng machine, the combination with a case-shiftmechanism, of acpair of case-shift levers adjacent each other, an adjustable lug on each lever, an arm for each lever adapted to be swung to frictionally engage said lugs, a rock member for said arms above the levers, a spring normally tending to release the arms, and a fingerpiece fast on the member whereby the arms may be made efi'ective.

8. In a typewritingmachine, the combination With a case-shift mechanism, of a pair of case-shift levers adjacent each other, an arm for each lever, a rock member to which said arms are fast, a lug on each lever adapted to be frictionally engaged by its arm to lock the lever down, means for separately adjusting each lug, and a finger-piece fast on said member to move the arms to effective position.

9. In a typewriting machine having a front Wall, in combination, a case-shift mechanism, a case-shift key-lever projecting through said front Wall, a movable locking member back of the front Wall, a lug back of said Wall and shiftably supported on said key-lever, means actuable at the front of said Wall for variably adjusting the lug on the lever, means normally urging said locking member to ineffective position, and means actuable at the front of said Wall for shifting said locking member to efi'ective position, the (so-operating surfaces on said looking member and lug being such that the friction therebetween Will maintain the locking member in efiective position but a slight depression of said key-lever Will permit said member to return to its normal position.

WILLIAM A. DOBSON.

Witnesses:

GEORGE W. CAMPBELL, M. S. EAKIN. 

